Differential in vitro activity of the DNA topoisomerase inhibitor idarubicin against Trypanosoma rangeli and Trypanosoma cruzi

In this study the effect of eight DNA topoisomerase inhibitors on the growth Trypanosoma rangeli epimastigotes in cell culture was investigated. Among the eight compounds tested, idarubicin was the only compound that displayed promising trypanocidal activity with a half-maximal growth inhibition (GI50) value in the sub-micromolar range. Fluorescence-activated cell sorting analysis showed a reduction in DNA content in T. rangeli epimastigotes when treated with idarubicin. In contrast to T. rangeli, against Trypanosoma cruzi epimastigotes idarubicin was much less effective exhibiting a GI50 value in the mid-micromolar range. This result indicates that idarubicin displays differential toxic effects in T. rangeli and T. cruzi. Compared with African trypanosomes, it seems that American trypanosomes are generally less susceptible to DNA topoisomerase inhibitors.

Antioxidant and antitopoisomerase activities in plant extracts of some Colombian flora from La Marcada Natural Regional Park

Many plants have been used to treat some diseases and infections since time immemorial, and this potential has been exploited by the pharmaceutical industry in the search of new analgesic, anticarcinogenic and antimicrobial agents, among other active agents. in order to contribute with bioprospection studies on the Colombian flora, 35 extracts from 13 plant species belonging to seven families (Apocynaceae, Cactaceae, Costaceae, Eremolepidaceae, Passifloraceae, Solanaceae and Urticaceae) were collected from La Marcada Natural Regional Park (LMNRP), Colombia. Dichloromethane, n-hexane and aqueous-methanol crude extracts were prepared and evaluated for their activity against Saccharomyces cerevisiae RS322N, R52Y and RS321 strains in the yeast mutant assay and their antioxidant capacity through the DPPH test. The dichloromethane extract from Myriocarpa stipitata (Urticaceae) showed moderate inhibitory activity against the three S. cerevisiae strains tested. The capacity of the dichloromethane extract from M. stipitata to inhibit the enzyme topoisomerase I and to cause DNA damage was inferred from these results. In the DPPH assay, the n-hexane crude extract from Costus sp. (Costaceae) showed good antioxidant activity (48%); in addition, the crude dichloromethane and aqueous-methanol extracts from Rhipsalis micrantha (Cactaceae) showed moderate antioxidant activity with percentage of 29 and 21%, respectively. Rev. Biol. Trop. 59 (3): 1089-1097. Epub 2011 September 01.

Desde tiempos inmemoriales, muchas plantas han sido usadas para el tratamiento de varias enfermedades e infecciones, este potencial ha sido explotado por la industria farmacéutica en la búsqueda de nuevos agentes analgésicos, anticancerígenos y antimicrobianos, entre otros. Consientes con esto, se evaluó la actividad de 35 extractos de 13 especies de plantas recolectadas en el Parque Regional Natural La Marcada (PRNLM, Colombia) contra las cepas mutadas de Saccharomyces cerevisiae RS322N, R52Y y RS321 en el ensayo de la levadura mutada y la capacidad antioxidante de los extractos a través del método del DPPH. El extracto crudo de diclorometano de Myriocarpa stipitata (Urticaceae) presentó actividad moderada contra las tres cepas de S. cerevisiae evaluadas. Lo cual permitió inferir la capacidad del extracto de diclorometano de esta especie para inhibir la enzima topoisomerasa I y causar daño al ADN. Además, en el ensayo del DPPH, el extracto de n-hexano crudo de Costus sp (Costaceae) mostró actividad antioxidante buena (48%), mientras que los extractos de diclorometano y acuoso metanólico crudos de Rhipsalis micrantha (Cactaceae) tuvieron actividad antioxidante moderada, con valores del 29 y 21%, respectivamente.